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Post by cubflyercameron on Mar 1, 2011 9:15:51 GMT 1
Hi all, quick question. As i cannot wait for shipping from Hobbycity, I found the following EMAX outrunner on our local trading site Trademe. The specs are followed and am just wondering if this motor has enough grunt to pull the super cub with power to spare, many thanks in advance
EMAX CF2822
Specs:-
Weight - 39gm
Max Thrust - 740gms
KV - 1200
Watts - 202W
Recommended Props - 8-10"
Lipo Cells - 2-3cells
Model weight - 200-400gms
The specs say the model weight should be within 200 to 400 grams, so am a bit wary of the motor being underpowered for the cub,
or perhaps
Emax CF2822 Outrunner Brushless motor.
This light weight powerful little motor which is an ideal replacement for 380 sized brushed motors.
The motor is suitable for all models of 300-400 size.
The EMAX CF2822 works well on a wide variety of models weighing up to 30 ounces. It will produce about 24 ounces of thrust using a 3 cell Lipo battery and the GWS 8040 prop.
Motor Specs
Battery : LiPo Battery (6-12V, 2-3 cells)
RPM/V : 1200kv
Input Voltage: 6-12V
Max Current: 15.5A
Max efficiency: 82%
Max efficiency current: 7-16A (>75%)
Recommended ESC: >18A
No load Current: 0.9A
Internal Resistance : 150Ohms
Weight - 40g
Recommended model weight: 200-800g
Recommended Prop without gearbox:
8X3.8
9X4.5
10X5
Motor Dimensions: 28.25mm , 48.5mm (Diameter, Length (inc shaft))
Shaft Dimensions: 3mm , 18mm (Diameter, Length)
Thrust:
710g / 1.5lbs with a 10X5 Prop at 11.1v
745g / 1.64lbs with a 9X4.5 Prop at 11.1v
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Post by Dillzio on Mar 1, 2011 10:23:40 GMT 1
stock cub weighs 750g, stock motor prop puts out around 600g throttle. All of those motors look fine.
when it says they're for a 200 to 300 size plane, they're talking motor size, not grams.
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Post by ginginho on Mar 1, 2011 12:24:07 GMT 1
I have one of these on one of my depron home brews. It's an OK motor but I'd have some reservations about using one on the SC. Firstly, I wouldn't run it with anything bigger than an 8" prop on a 3S, it will pull too much current. The watts figure listed is total doggy doo-doo, it's more around the 120-130W mark. I don't think you'll have power to spare, I'd say the performance would be adequate, no more than that.
I'm not sure it falls into the bucket of B/L outrunners that Fly dislikes due to the shaft being soft and bendy, but it may not handle nosing over too well. I use mine as a pusher with a prop saver so the shaft is never stressed.
If they have other Emax motors, then you could do worse than either the 2215/20 (lower power of these two but more than the 2822) or the 2810/12 (plenty of grunt). These will be a fair bit more expensive though. Size your ESC accordingly.
Contrary to what Dillz has said, it is suitable for a model that weighs 200-400 gramme, as the first list of specs state. The cub is considerably heavier than this.
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Post by cubflyercameron on Mar 2, 2011 4:04:06 GMT 1
The 2nd one I listed seems ok to me but I think I'll play it safe with a Turnigy or perhaps even a parkzone trojan motor. I would rather get a motor suited to the super cub that others have had good experiences than use one that I've heard of no one using and having bad luck.
Thanks for the input.
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Post by flydiver on Mar 2, 2011 5:25:08 GMT 1
These are probably more realistic values for that motor: www.headsuprc.com/servlet/the-1516/EMAX-CF2822-Outrunner-Brushless/DetailFigure the stock motor is a 13A with lipo for reference. Realistically you are working in the same general power band with a bit higher KV (faster) motor. You would be carrying less weight but that's an issue since you still have to achieve CG. I rewound one for a friend and easily bumped it up to a 20A motor. |
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Post by ginginho on Mar 2, 2011 12:44:20 GMT 1
One other observation about these motors, the set screws that hold the motor to the mounting bracket are prone to working loose. If you use one of these, apply some thread lock to these and check them regularly.
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Post by flydiver on Mar 2, 2011 18:40:51 GMT 1
One other observation about these motors, the set screws that hold the motor to the mounting bracket are prone to working loose. If you use one of these, apply some thread lock to these and check them regularly. The issue there is set SCREWS - 2 of them. This is a bad design for motor mounts. If you tighten BOTH firmly the motor bearing tube ends up being kind of suspended on the points of 2 set screws. If one loosens up the other one ends up being of little or no value. Better is to tighten ONE WELL. This pushes the bearing tube up tightly against the much larger opposite surface of the mount on the opposite side. You have higher friction, a snugger mount, and a more stable system. Then just modestly snug the 2nd set screw-mostly to not lose it so you have a backup. Do not tighten the 2nd screw hard. Blue loctite is certainly desirable for that screw, probably for both. |
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Post by john66 on May 26, 2011 11:42:28 GMT 1
If they have other Emax motors, then you could do worse than either the 2215/20 (lower power of these two but more than the 2822) or the 2810/12 (plenty of grunt). These will be a fair bit more expensive though. Size your ESC accordingly. Just fitted my Emax 2215/20 you recommended at Blackbushe Nick. Cheers, bit more glue on her split side and shes up n running again! Up for a cpl of hours an afternoon soon Nick? So this emax will make my cubby more stock again, though im guessing not quite just by the fact its a more efficient motor being brushless? John |
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Post by ginginho on May 26, 2011 12:40:26 GMT 1
I've just rechecked the spec's of this, it's going to be more pokey than the stock setup, not as mad as what everyone seems to be fitting these days. It looks quite a versatile motor, with plenty of options for prop sizing and subsequent power output.
Check your CoG, it probably will have moved.
I could be up for a bit a flight, I'm not sure what's on the cards this weekend. I'll check and also see what the weather has in store. Are you going to come over my way?
If we do meet I should be able to bring a selection of props for you to try if you want. What are you using to fit props, what diameter hole?
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Post by john66 on May 26, 2011 12:48:15 GMT 1
Cheers Nick, I'll check prop shaft diameter in abit. Yes I meant down your way unless you're up for a trip......Maybe we could go to ahem, hate to say it to your Pompey ears, but ahem cough splutter S'hampton, Southampton! There I said it! Sorry mate. Pipe up Renard! Though this weekend is out for me.
I'll email you about flying now.
John
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Post by mythotical on May 26, 2011 15:39:30 GMT 1
The t-28 motor is great, I just needed to adjust the AOA a little, the SC tends to climb under full throttle. All I needed was to put a paint stirring stick under the wing at the back of the saddle. Now I have a SC that will do blenders and spins like a top when doing so. Knife edge is almost possible, I think I will need to stiffen the rudder to do so. ;D
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Post by john66 on May 26, 2011 15:48:46 GMT 1
The t-28 motor is great, I just needed to adjust the AOA a little, the SC tends to climb under full throttle. I was under the impression from previous posts on here, that throttle controls altitude and elevator speed. I know it sounds backwards but it is so? Input please more knowledgable ones? John |
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Post by ginginho on May 26, 2011 17:09:24 GMT 1
The t-28 motor is great, I just needed to adjust the AOA a little, the SC tends to climb under full throttle. I was under the impression from previous posts on here, that throttle controls altitude and elevator speed. I know it sounds backwards but it is so? Input please more knowledgable ones? John That is the case in simple terms based on straight and level flight and airspeed but they tend to be linked. Increased throttle on it's own won't increase the airspeed, but it will cause the aircraft to climb. Commonly the elevator is adjusted to keep the same altitude and hence the airspeed increases. Similarly, reducing the throttle doesn't slow the aircraft, it causes it to lose altitude, again elevator is applied to hold it level and as a consequence lose airspeed. Reducing the AoA means that less lift is generated with the same power applied and hence the climb rate is reduced. |
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Post by john66 on May 26, 2011 18:04:40 GMT 1
I was under the impression from previous posts on here, that throttle controls altitude and elevator speed. I know it sounds backwards but it is so? Input please more knowledgable ones? John That is the case in simple terms based on straight and level flight and airspeed but they tend to be linked. Increased throttle on it's own won't increase the airspeed, but it will cause the aircraft to climb. Commonly the elevator is adjusted to keep the same altitude and hence the airspeed increases. Similarly, reducing the throttle doesn't slow the aircraft, it causes it to lose altitude, again elevator is applied to hold it level and as a consequence lose airspeed. Reducing the AoA means that less lift is generated with the same power applied and hence the climb rate is reduced. Ahh thats why the throttle makes her smaller! ;D John |
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Post by leisureshoot on May 29, 2011 15:26:46 GMT 1
That is the case in simple terms based on straight and level flight and airspeed but they tend to be linked. Increased throttle on it's own won't increase the airspeed, but it will cause the aircraft to climb. Commonly the elevator is adjusted to keep the same altitude and hence the airspeed increases. Similarly, reducing the throttle doesn't slow the aircraft, it causes it to lose altitude, again elevator is applied to hold it level and as a consequence lose airspeed. Reducing the AoA means that less lift is generated with the same power applied and hence the climb rate is reduced. Ahh thats why the throttle makes her smaller! ;D John Yes, get crazy with the throttle, and it is nothing but small pieces left to pick up.  |
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